Any capture card will supply you with a video in. But in order to control your cable box, aka change the channel, you will need one that has a IR blaster. I've been using a Hauppauge PVR-150 with my satellite box for several years now to have my own PVR that can change the channel for me.

The only difference is that one comes with a remote plus other doo-dads and the other does not?

This snippet from the discription of the "Hauppauge WinTV-HVR-1850 MC Board Only" confused me a little.

The WinTV-HVR-1850 board adds on-board Media Center and WinTV remote control receiver/blaster. Now you can get IR receive and blast for both Media Center and the WinTV v7 application, without needing an external "beanbag".

And also even though these have tv tuners I would still need to buy an HD antenna to watch over the air tv correct?

Deep in the human unconscious is a pervasive need for a logical universe that makes sense. But the real universe is always one step beyond logic.